AUSTIN, Texas (AP) -- A sweeping bill that would effectively shut down most abortion clinics across the nation's second most-populous state has stalled in the Texas Senate -- and a Democratic filibuster that will only need to last a seemingly manageable 13 hours Tuesday looks like it will be enough to talk the hotly contested measure to death.

After thwarting two attempts Monday by majority Republicans to bring the abortion bill to a floor vote ahead of its scheduled time Tuesday morning, Democrats are turning to Sen. Wendy Davis, D-Fort Worth, to stage the marathon speech.

"We want to do whatever we can for women in this state," Sen. Kirk Watson of Austin, leader of the Senate Democrats.

The bill would ban abortion after 20 weeks of pregnancy and force many clinics that perform the procedure to upgrade their facilities and be classified as ambulatory surgical centers. Also, doctors would be required to have admitting privileges at a hospital within 30 miles -- a tall order in rural communities.

Although Texas is just the latest of several conservative states to try to enact tough limits on abortions, the scope of its effort is notable because of the combination of bills being considered and the size of the state.

When combined in a state 773 miles wide and 790 miles long and with 26 million people, the measures would become the most stringent set of laws to impact the largest number of people in the nation.

"If this passes, abortion would be virtually banned in the state of Texas, and many women could be forced to resort to dangerous and unsafe measures," said Cecile Richards, president of Planned Parenthood Action Fund and daughter of the late former Texas governor Ann Richards.

Outnumbered 19-11 -- with San Antonio Sen. Leticia Van de Putte missing to attend the funeral of her father, who died last week in a car crash -- Senate Democrats held firm Monday their razor-thin margin of a single vote to block the bill from moving forward.

That's key since the 30-day special legislative session ends at midnight Tuesday, meaning the filibuster Democrats have promised only needs to last the better part of one day, instead of two.

Davis gave a filibuster at the end of the 2011 session to temporarily block $5.4 billion cuts to public schools, and said she was preparing for her upcoming one speech but refused to say exactly how.

She will have to speak nonstop, remain standing, refrain from bathroom breaks or even leaning on anything. Other Democrats can give her voice a break by offering questions to keep conversation moving.

"Democrats chose not to negotiate, and we could not get the block undone," said Lt. Gov. David Dewhurst, a Republican who controls the flow of Senate legislation. He refused to declare the issue dead -- but others were less optimistic.

Sen. Dan Patrick, R-Houston, said the Democrats never should have been allowed to put Republicans "in a box" and complained that many in the Senate GOP were "flying by the seat of their pants."

But the bill's bogging down began with Gov. Rick Perry, who summoned lawmakers back to work immediately after the regular legislative session ended May 27, but didn't add abortion to the special session to-do list until late in the process. The Legislature can only take up issues at the governor's direction during the extra session.

Then, House Democrats succeeded in stalling nearly all night Sunday, keeping the bill from reaching the Senate until 11 a.m. Monday.

The measure only passed the lower chamber after a raucous debate that saw more than 800 women's rights activists pack the public gallery and surrounding Capitol, imploring lawmakers not to approve it.

While supporters say it will protect women's health, abortion rights groups warn the practical effect of the bill would be to shutter most abortion providers statewide -- making it very difficult for Texas women to have the procedure.

Debate ranged from lawmakers waving coat-hangers on the floor and claiming the new rules are so draconian that women are going to be forced to head to drug war-torn Mexico to have abortions, to the bill's sponsor, Republican Rep. Jodie Laubenberg of Spring, errantly suggesting that emergency room rape kits could be used to terminate pregnancies.

In the end, though, the bill passed by more than 60 votes as Republicans and some conservative Democrats approved it.

Still, Legislature rules prohibit the Senate from taking up a bill for 24 hours after it clears the House. Republicans struggled to find a way to break the Democratic roadblock, but the vote swung Monday on Sen. Eddie Lucio, a Brownsville Democrat who voted for the abortion bill when it first passed the Senate a week ago but pledged not to approve suspending the rule with Republicans unless Van de Putte was able to make it to the chamber.

She didn't show and Lucio voted with his party, despite his support for the bill.

If the abortion restrictions go down, though, other measure could also fall with it. A proposal to fund major transportation projects as well as a bill to have Texas more closely conform with a recent U.S. Supreme Court decision banning mandatory sentences of life in prison without parole for offenders younger than 18 might not get votes. Current state law only allows a life sentence without parole for 17-year-olds convicted of capital murder.

Watson said Democrats are willing to pass the transportation and 17-year-old sentencing measures but won't budge on abortion.

"Let's get those up, let's get those out of here," Watson said. "Let's not make these victims of red-meat politics."

Patrick said that if the filibuster succeeds, he hopes Perry will summon lawmakers back for a second or even third special session.

"If the majority can't pass the legislation that they believe is important and the people believe is important," he said, "than that's of great concern to me."